The tftp "windowsize" greatly improves the performance of tftp
transfers. This patchset adds support for it.
The first two patches are a little bit unrelated and enhance the 'cp
-v' output by giving information about the transfer speed. They can
be dropped if they are unwanted.
I tested the function with an iMX8MP platform in three environments:
- at home over OpenVPN on an ADSL 50 line --> 27x speedup
- 1 Gb/s connection --> 9x speedup
- connection over 100 Mb/s switch --> 4x speedup
In the test, I downloaded variable sized files which were filled from
/dev/urandom. E.g.
| :/ global tftp.windowsize=128
| :/ cp -v /mnt/tftp/data-100MiB /tmp/data && sha1sum /tmp/data
| [################################################################] 104857600 bytes, 98550375 bytes/s
For slow connection speeds, smaller files (1MiB, 4 MiB + 20 MiB) were
used.
The numbers (bytes/s) are
| windowsize | VPN | 1 Gb/s | 100 Mb/s |
|------------|-----------|------------|------------|
| 128 | 3.869.284 | 98.643.085 | 11.434.852 |
| 64 | 3.863.581 | 98.550.375 | 11.434.852 |
| 48 | 3.431.580 | 94.211.680 | 11.275.010 |
| 32 | 2.835.129 | 85.250.081 | 10.985.605 |
| 24 | 2.344.858 | 77.787.537 | 10.765.667 |
| 16 | 1.734.186 | 67.519.381 | 10.210.087 |
| 12 | 1.403.340 | 61.972.576 | 9.915.612 |
| 8 | 1.002.462 | 50.852.376 | 9.016.130 |
| 6 | 775.573 | 42.781.558 | 8.422.297 |
| 4 | 547.845 | 32.066.544 | 6.835.567 |
| 3 | 412.987 | 26.526.081 | 6.322.435 |
| 2 | 280.987 | 19.120.641 | 5.494.241 |
| 1 | 141.699 | 10.431.516 | 2.967.224 |
|------------|-----------|------------|------------|
| unpatched | 140.587 | 10.553.301 | 2.978.063 |
Patchset has been tested with
| for i in data-0 data-100B data-1KiB data-1432B data-64KiB data-1MiB data-4MiB; do
| tftp "$i"
| tftp -p "$i"
| done
against tftp servers with and without rfc 2747 support (OACK).
The window size related parts of the patchset (with deactivated
selftest) increase the barebox binary size by
| add/remove: 6/0 grow/shrink: 7/2 up/down: 1572/-32 (1540)
| Function old new delta
| tftp_handler 756 1324 +568
| tftp_allocate_transfer - 196 +196
| tftp_put_data - 184 +184
| tftp_window_cache_remove - 124 +124
| tftp_window_cache_get_pos - 120 +120
| tftp_send 296 412 +116
| tftp_do_open 428 512 +84
| tftp_states - 72 +72
| tftp_do_close 260 312 +52
| tftp_init 16 60 +44
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=629556, After=631096, chg +0.24%
Turning of the datagram cache (CONFIG_FS_TFTP_REORDER_CACHE_SIZE=0)
reduces the overhead to
| add/remove: 3/0 grow/shrink: 6/2 up/down: 808/-32 (776)
| Function old new delta
| tftp_handler 756 1092 +336
| tftp_allocate_transfer - 144 +144
| tftp_send 296 412 +116
| tftp_do_open 428 512 +84
| tftp_states - 72 +72
| tftp_init 16 60 +44
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=629556, After=630332, chg +0.12%
Restoring the old behaviour by CONFIG_FS_TFTP_MAX_WINDOW_SIZE=1 shows
an overhead of
| add/remove: 3/0 grow/shrink: 6/2 up/down: 720/-32 (688)
| Function old new delta
| tftp_handler 756 1088 +332
| tftp_allocate_transfer - 144 +144
| tftp_do_open 428 512 +84
| tftp_states - 72 +72
| tftp_init 16 60 +44
| tftp_send 296 328 +32
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=629556, After=630244, chg +0.11%
Enrico Scholz (21):
tftp: add some 'const' annotations
tftp: allow to change tftp port
cmd:tftp: add '-P' option to set tftp server port number
tftp: do not set 'tsize' in WRQ requests
tftp: assign 'priv->block' later in WRQ
tftp: minor refactoring of RRQ/WRQ packet generation code
tftp: replace hardcoded blksize by global constant
tftp: remove sanity check of first block
tftp: add debug_assert() macro
tftp: allocate buffers and fifo dynamically
tftp: add sanity check for OACK response
tftp: record whether tftp file is opened for lookup operation only
tftp: reduce block size on lookup requests
tftp: refactor data processing
tftp: detect out-of-memory situations
tftp: implement 'windowsize' (RFC 7440) support
tftp: do not use 'priv->block' for RRQ
tftp: reorder tftp packets
tftp: add selftest
tftp: accept OACK + DATA datagrams only in certain states
tftp: add some documentation about windowsize support
Documentation/filesystems/tftp.rst | 38 ++
commands/tftp.c | 22 +-
fs/Kconfig | 36 ++
fs/tftp-selftest.h | 56 +++
fs/tftp.c | 763 +++++++++++++++++++++++++----
test/self/Kconfig | 7 +
6 files changed, 824 insertions(+), 98 deletions(-)
create mode 100644 fs/tftp-selftest.h
---
v3 -> v4
- fix operation with non rfc 2347 servers
- do not send 'tsize' in WRQ requests
- add more sanity checks
- add some documentation
v2 -> v3
- use "port=XX" mount options instead of global 'tftp.port' variable
- allocate fifo and send buffer dynamically based on block- and
window size of the transfer. Do not use fixed constants anymore
- rewritten cache code; use bitmap based functions with O(1)
complexity instead of iterating over (small) arrays
- unittest for cache functions
- add information about binary sizes
v1 -> v2
- fixes for non rfc7440 servers
--
2.37.2
